Series or parallel?

[jake1]

Putting two xle-4040s together with a procon 330 behind them. Just looking for advise on plumbing them in parallel or series and the pros and cons of each. I'm trying to process .8% birch sap quickly and not to a high brix. Maybe 5-7 brix. Thanks for you thoughts
Jake

[wiam]

Faster water removal in parallel.

[Clinkis]

Be iffy if a 330 gph procon pump would have enough flow to run 2 xle4040s in parallel. They would foul fairly quickly. Series would be better to help keep flows up across membrane. I run a single xle4040 with a 190gph procon and I wouldn't want any less. That will only give 165 gph per membrane. I agree with Wiam that parallel would give you faster water removal but you will probably need a bigger pump.

[jake1]

You think I'd have fouling issues in parallel even if I was not making high brix? Wonder how much difference in gph it makes between series and parallel. Not apposed to either just want to make the most efficient setup

[arcticmaple8]

done it both ways. i vote series

[BreezyHill]

series...4040s work most efficiently at 10-13 gallons per minute. 330/60=5.5 gpm so in a parallel setup you will be only at 2.25 gpm. In series you will get a higher brix from your concentrate flow in a single pass. You can go to Dow's site and look at the spec sheets and with that size pump parallel will have a flow limitation issue.

On a larger pump like the series 5 or 6 with 600gph I would go parallel. Install a couple extra valves for washing so that you run them parallel, to get the best cleaning results by not washing from #1 and stuff #2 full. That was my issue for the last 3 seasons. $30 in valves and another pair of vessels for our machine next season.

Good Luck!

[jake1]

So with them in series they should have the same flow rate through each membrane as just having one membrane. So I would be gaining quite a bit of efficiency by adding a second post and my pump would be able to keep up or can a 330 even keep up with two xle's at all? Just curious if adding a second post will make much difference.

[BreezyHill]

Jake, the difference will be that the concentrate will be higher in sugar. Think of it like this. You RO sap in take one until it is empty on a single post. You then batch from tank #2 back to #1. You will have a higher sugar level after the second pass thru the RO. With a second membrane in series you will nearly duplicate this result in a single pass. It is nearly the same due to there will be a small pressure drop between post #1 and Post #2. From memory I think the pressure drop is not more than 10#. So if you are running 125 you should be hitting #2 at 115# and still getting a very good result from post#2. The pressure drop is more at the beginning of a run and less as the membrane starts to clog and less permeate pass through the membrane, on my unit.

Dow tech guys are more than happy to help the maple producer but it is difficult at first since they are working 99.9% of the time in the reverse of us. What we discard is what they strive to optimize. Permeate. Our concentrate is dirty water to them and goes back in the ocean or down stream. The guy I spoke at length with was horrified that we dump that pure water on the ground..."you should be selling that to towns or schools or somebody that wants the purest water on earth. Its filtered by a tree then an RO".

[jake1]

Thanks for the help. I'm stoked!